Clinton County is county located in the U.S. state of Missouri and is part of the Kansas City metropolitan area. As of the 2020 U.S. Census, the county had a population of 21,184. Its county seat is Plattsburg. The county was organized January 2, 1833, and named for Governor DeWitt Clinton of New York. The county seat of Plattsburg derives its name from a town of a similar name that is the county seat of Clinton County, New York, which was also named for the Governor.
According to the U.S. Census Bureau, the county has a total area of , of which is land and (1.1%) is water.
As of the 2020 census, the county had a population of 21,184. The median age was 42.4 years. 23.4% of residents were under the age of 18 and 19.7% of residents were 65 years of age or older. For every 100 females there were 99.8 males, and for every 100 females age 18 and over there were 98.9 males.
The racial makeup of the county was 91.7% White, 1.0% Black or African American, 0.4% American Indian and Alaska Native, 0.4% Asian, 0.0% Native Hawaiian and Pacific Islander, 0.6% from some other race, and 5.9% from two or more races. Hispanic or Latino residents of any race comprised 2.4% of the population.
24.2% of residents lived in urban areas, while 75.8% lived in rural areas.
There were 8,173 households in the county, of which 31.4% had children under the age of 18 living with them and 20.8% had a female householder with no spouse or partner present. About 24.5% of all households were made up of individuals and 11.6% had someone living alone who was 65 years of age or older.
There were 8,934 housing units, of which 8.5% were vacant. Among occupied housing units, 76.9% were owner-occupied and 23.1% were renter-occupied. The homeowner vacancy rate was 1.2% and the rental vacancy rate was 8.5%.
As of the census of 2017, there were 20,554 people, 8,990 households, and 8,299 families residing in the county. The population density was . There were 7,877 housing units at an average density of . The racial makeup of the county was 95.5% White, 1.4% Black or African American, 0.7% Native American, 0.4% Asian, 0.01% Pacific Islander, 0.27% from other races, and 1.9% from two or more races. Approximately 2.1% of the population were Hispanic or Latino of any race.
There were 7,152 households, out of which 34.90% had children under the age of 18 living with them, 61.40% were married couples living together, 8.80% had a female householder with no husband present, and 25.90% were non-families. 22.00% of all households were made up of individuals, and 10.50% had someone living alone who was 65 years of age or older. The average household size was 2.59 and the average family size was 3.03.
In the county, the population was spread out, with 26.80% under the age of 18, 7.40% from 18 to 24, 28.20% from 25 to 44, 23.50% from 45 to 64, and 14.10% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 96.00 males. For every 100 females age 18 and over, there were 91.60 males.
The median income for a household in the county was $57,486, and the median income for a family was $48,244. Males had a median income of $36,307 versus $22,991 for females. The per capita income for the county was $19,056. About 7.30% of families and 9.30% of the population were below the poverty line, including 11.30% of those under age 18 and 12.70% of those age 65 or over.
School districts with territory in the county include:
The Republican Party predominantly controls politics at the local level in Clinton County. Republicans hold all but one of the elected positions in the county.
Clinton County is split into two Missouri House of Representatives District numbers 8 & 9. This change occurred after the mandatory redistricting caused by the 2020 census.
All of Clinton County is a part of Missouri's 12th District in the Missouri Senate and is currently represented by Rusty Black (R-Chillicothe, MO).
All of Clinton County is included in Missouri's 6th Congressional District and is currently represented by Sam Graves (R-Tarkio) in the U.S. House of Representatives.